<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <button>发送请求</button>
    <script>
        let oBtn = document.querySelector('button');
        oBtn.onclick = function(){
            const xhr = new XMLHttpRequest();
            xhr.open('get', 'http://localhost:8080/testie?t='+Date.now());
            xhr.send();
            xhr.onreadystatechange = function(){
                if(xhr.readyState === 4){
                    if(xhr.status >= 200 && xhr.status < 300){
                        console.log(xhr.response);
                        console.log(xhr.getResponseHeader('content-type'));
                        console.log(xhr.getAllResponseHeaders());
                    }
                }
            }
        }
    </script>
</body>
</html>